High-efficiency, high-power, stable 172 nm xenon excimer light source

Salvermoser, M.; Murnick, D. E.

doi:10.1063/1.1605798

Cited by 19 publications

(16 citation statements)

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“…In fact in a different wavelength range (172 nm) xenon excimer lamps [58] with rated lifetimes of 50,000 to 100,000 hrs, are already in commercial use [34], providing (using appropriate phosphors) both interior and exterior office lighting, for example on the Rotterdam KPN Telecom tower [59].…”

Section: Discussionmentioning

confidence: 99%

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

et al. 2013

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Background0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ∼200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure.AimsThe aim of this work was to test the biophysically-based hypothesis that ∼200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues.MethodsA Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue.ResultsWe found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp.ConclusionsAs predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug-resistant origin.

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Section: Discussionmentioning

confidence: 99%

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

et al. 2013

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“…[7][8][9] At that time, some UV-C emitting luminescent materials activated by Pr 3+ have since become less interesting due to the toxic character of these materials.…”

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confidence: 99%

“…[7][8][9] At that time, some UV- have since become less interesting due to the toxic character of these materials. One of the most efficient UV-C emitting materials, which also has a rather high thermal quenching temperature, is YPO 4 :Bi .…”

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confidence: 99%

Cathodoluminescence and Photoluminescence of YPO₄:Pr³⁺, Y₂SiO₅:Pr³⁺, YBO₃:Pr³⁺, and YPO₄:Bi³⁺

Broxtermann

Engelsen

Fern

et al. 2017

ECS J. Solid State Sci. Technol.

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Herein we describe the synthesis, characterization, and cathodoluminescence of the UV emitting phosphors YPO 4 :Pr 3+ , Y 2 SiO 5 :Pr 3+ , YBO 3 :Pr 3+ , and YPO 4 :Bi 3+ . These photoluminescent UV phosphors exhibited strong luminescence in the UV part of the electromagnetic spectrum when excited by electron bombardment. Spectra have been recorded between 210 and 650 nm at electron beam energies of 5, 10 and 15 keV. The energy efficiencies of YPO 4 :Pr 3+ , Y 2 SiO 5 :Pr 3+ , YBO 3 :Pr 3+ and YPO 4 :Bi 3+ in the UV range were 9.2%, 2.7%, 5.1%, and 7.2%, respectively at 15 keV. UV photoluminescence measurements were conducted using 160 nm excitation generated by combining a VUV monochromator with a deuterium lamp. The UV emitting phosphor Y 2 SiO 5 :Pr 3+ has attracted attention both because of its potential application as a UV tunable laser and also as a scintillator arising from its short decay time (of about 40 ns).1-4 Moreover, it is one of the first UV emitting materials, which manifests up-conversion of blue radiation into the UV-C range. 5Interest rose in UV-A and UV-B emitting luminescent materials after the introduction of low-pressure Hg discharge lamps that were developed as sun tan lamps in the middle of the 20 th century. 6 The early UV emitting phosphors were activated by Tl + , Pb 2+ , or Bi 3+ , while later Ce 3+ activated phosphors such as LaPO 4 :Ce and YPO 4 :Ce came into play due to their better stability and environmental compliance as they contained no hazardous elements.The development of phosphors emitting in the UV-C range was stimulated by the advent of efficient dielectric barrier Xe discharge lamps some decades ago. [7][8][9] At that time, some UV- have since become less interesting due to the toxic character of these materials. One of the most efficient UV-C emitting materials, which also has a rather high thermal quenching temperature, is YPO 4 :Bi .10 However a serious drawback with this material is the limited stability of Bi 3+ cations toward oxidation or reduction. This necessitated a search for efficient and long-term stable Pr 3+ activated materials, since it is thought that Pr 3+ can withstand the harsh conditions of VUV radiation and the electron bombardment inside an excimer discharge tube. The most efficient materials amongst the many, which have been published so far are YPO 4 :Pr, LaPO 4 :Pr, Y 2 SiO 5 :Pr, YBO 3 :Pr, Ca 9 Y(PO 4 ) 7 :Pr, LuBO 3 :Pr, Lu 2 SiO 5 :Pr and LuPO 4 :Pr. The later Lutetium containing compounds are also regarded as scintillators because of their high density.Xe excimer discharge lamps containing a UV-C phosphor for germicidal action and photochemical purposes have been developed by several groups 11-13 and lamp products containing YPO 4 :Nd, YPO 4 :Pr, YPO 4 :Bi, and LaPO 4 :Pr were introduced several years ago. Even though these lamps can achieve wall plug efficiency close to that of low-and medium-pressure Hg discharge lamps, their commercial success is rather moderate so far. The main reason for this observation is their lower long-term stabi...

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“…We have found cases in which about one-third of the nuclear reaction energy is converted to FUV emissions by noble-gas excimer molecules. Such high conversion efficiencies have been encountered previously in electric discharges [3][4][5][6] , irradiation of noble gases by beams of electrons [7-9] and proton [10] bombardment of noble gases. Here they are reported for the first time in the context of a nuclear reaction and put on a quantitative basis needed to evaluate their applicability in a new FUV-based neutron detector.Following previous work [11], we started with a gas cell containing pure 3 He and 3 He/ 4 He mixtures, exposed to neutrons with a deBroglie wavelength of 0.384 ± 0.004 nm, produced at the NIST Center for Neutron Research.…”

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confidence: 74%

“…results in a base pressure of about 3 x 10 -8 kPa. After baking and evacuating the cell to the base pressure, we introduced ultrahigh purity 3 He into it with a gas handling system. This consists of a stainless steel manifold connected to the gas cell through a Microtorr, Model MC1-902-F filter to remove trace contaminants from the gas.…”

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confidence: 99%

Far-ultraviolet signatures of the H3e(n,tp) reaction in noble gas mixtures

Hughes

Coplan

Thompson

et al. 2010

Applied Physics Letters

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Previous work showed that the 3 He(n,tp) reaction in a cell of 3 He at atmospheric pressure generated tens of far-ultraviolet photons per reacted neutron. Here we report amplification of that signal by factors of 1000 and more when noble gases are added to the cell. Calibrated filter-detector measurements show that this large signal is due to noble-gas excimer emissions, and that the nuclear reaction energy is converted to far-ultraviolet radiation with efficiencies of up to 30%. The results have been placed on an absolute scale through calibrations at the NIST SURF III synchrotron. They suggest possibilities for highefficiency neutron detectors as an alternative to existing proportional counters.The 3 He(n,tp) process, in which a neutron reacts with a helion to produce a proton and a triton with excess energy of 764 keV, is one of the best-characterized neutron reactions [1]. This reaction is the trigger mechanism for the 3 He proportional counter, which is presently one of the most widely-used neutron detectors [2]. Here we discuss using the same trigger reaction to initiate far-ultraviolet (FUV) optical emissions, rather than electrical discharges. We have found cases in which about one-third of the nuclear reaction energy is converted to FUV emissions by noble-gas excimer molecules. Such high conversion efficiencies have been encountered previously in electric discharges [3][4][5][6] , irradiation of noble gases by beams of electrons [7-9] and proton [10] bombardment of noble gases. Here they are reported for the first time in the context of a nuclear reaction and put on a quantitative basis needed to evaluate their applicability in a new FUV-based neutron detector.Following previous work [11], we started with a gas cell containing pure 3 He and 3 He/ 4 He mixtures, exposed to neutrons with a deBroglie wavelength of 0.384 ± 0.004 nm, produced at the NIST Center for Neutron Research. At this wavelength, the cross section for the reaction 3 He(n,tp) reaction is (1.135 ± 0.012) x 10 -20 cm 2 . We measured FUV emissions in the cell with a filter-detector package that was calibrated at the NIST SURF III Synchrotron Ultraviolet Radiation Facility. This package is discussed below, as are the procedures for absolute measurements of the neutron flux and modeling of the optical detection system. The combination of measurement and modeling enables us to determine the number of FUV photons produced per neutron reaction.In the work with pure 3 He and 3 He/ 4 He mixtures the source of the optical signal was determined to be Lyman α radiation from the 2p states of the 1 H and 3 H formed as neutralization and excitation products of the 3 He(n,tp) process [11,12]. We found that, at a 3 He pressure of 100 kPa, tens of FUV photons are produced for every reacted neutron. This number is already encouraging as concerns the prospects for an absolute neutron detector based on FUV emissions vs. the electrical discharges that drive proportional counters, as discussed previously [11]. When mixtures of Ar, Kr or Xe are added to the 3 He...

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High-efficiency, high-power, stable 172 nm xenon excimer light source

Cited by 19 publications

References 14 publications

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

Cathodoluminescence and Photoluminescence of YPO₄:Pr³⁺, Y₂SiO₅:Pr³⁺, YBO₃:Pr³⁺, and YPO₄:Bi³⁺

Far-ultraviolet signatures of the H3e(n,tp) reaction in noble gas mixtures

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High-efficiency, high-power, stable 172 nm xenon excimer light source

Cited by 19 publications

References 14 publications

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

207-nm UV Light - A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. I: In Vitro Studies

Cathodoluminescence and Photoluminescence of YPO4:Pr3+, Y2SiO5:Pr3+, YBO3:Pr3+, and YPO4:Bi3+

Far-ultraviolet signatures of the H3e(n,tp) reaction in noble gas mixtures

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Cathodoluminescence and Photoluminescence of YPO₄:Pr³⁺, Y₂SiO₅:Pr³⁺, YBO₃:Pr³⁺, and YPO₄:Bi³⁺